The overall goals of this renewal application cover primarily the molecular, immunological, pharmacological, regulatory and functional aspects of protein kinase C (PKC) in cell growth and differentiation. The activity level, immunoreactivity and immunocytochemical localization (both at the light and electron microscopic level of PKC, using anit-PKC antisera developed in the PI's lab, and phosphorylation of endogenous substrate proteins for PKC in HL60, K562, KG-1, KG-1a, CHO and E7SKS cells will be examined, so that the role of the PKC system in the TPA- induced cell differentiation can be assessed. Similar studies will be conducted using BHK-21 and its temperature sensitive mutants (blocked at different phases of cell cycle), and BALB/c-3T3 and its transformed sublines (M-MSV, K-BALB and 3T12-3), so that the role of the PKC system in cell cycle progression and cell growth can be further investigated. In addition, the effects of existing anti-cancer agents and synthetic analogs of alkyllsophospholipid and phosphatidylcholine on PKC activity and directional PKC translocaton, protein phosphorylation and cell differentiation induced by TPA will be examined, so that PKC can be established as a potential site of actions of these agents. It is hoped that the proposed research would yield new knowledge regarding the regulation of cell growth and differentiation, which would potentially aid cancer prevention and therapy.